Artificial silk dry spinning apparatus



1943. J. J. CALHOUN 2,327,399

I ARTIFICIAL SILK DRY SPINNING APPARATUS Filed Dec. 18, 1941 James I.Calhnun Patented Aug. 24, 1943 ARTIFICIAL SILK DRY SPINNING APPARATUSJames J. Calhoun, Waynesboro, Va., asslgnor to E. I. du Pont de Nemours& Company, Wilmington, Del., a corporation of Delaware ApplicationDecember 18, 1941, Serial No. 423,554

1 Claim.

This invention relates to new and improved apparatus for application tospinning cells used in the dry or evaporative method of spinningartificial filaments. More particularly the invention relates to new andimproved apparatus for introducing air or other evaporative mediumimmediately adjacent the face of the spinneret in the spinning cell.

The manner in which solvent is removed from gel filaments of celluloseacetate yarn or the like formed by the evaporative spinning methodwithin the first few inches of travel from the spinneret face is allimportant in determining the characteristics of the yarn formed. In amodern cellulose acetate spinning plant, spinning speeds are relativelyhigh and the yarn travels through this critical distance in about oneone-hundredth of a second. Furthermore, in order to get umformity ofresults and continuity of spinning, each and every filament comprisingthe yarn should be subjected to the same conditions of initial drying orevaporation of solvent. Moreover, for economy of operation, it isimportant that the evaporative medium exhausted from the spinning celland passed to the solvent recovery system be rich in solvent vapors. Yeton the other hand, air heavily laden with solvent vapors is of littlevalue in evaporating more solvent from the yarn. It is, therefore,important to present evaporative medium relatively free from solventvapors to each of the filaments issuing from the spinneret and at thesame time to use this evaporative medium in a highly efllcient manner,that is, use a relatively small quantity to pick up the maximumallowable amount of solvent.

This essential uniform and efiicient circulation of air or otherevaporative medium about the various filaments of the bundle in closeproximity to the spinneret is satisfactorily achieved by the vane doordescribed in the Williams application, Serial No. 306,649 filed November29, 1939, U. S. P. 2,285,245, but the location of the radial vanes abouta central point immediately opposite the face of the spinneret makes itimpossible for the operator to view the filaments coming from thespinneret; hence slow holes or plugged holes in the spinneret cannotreadily be detected.

An object of this invention, therefore, is to pro-- vide simple meansfor uniformly and efflciently circulating air or other evaporativemedium about the individual filaments issuing from the spinneret in thehead of a dry spinning cell, integrally coupled with means for visuallyinspecting the zone immediately adjacent the face of the spinneret.

Another object is to provide an mproved door or closure member assemblyfor the head of the spinning cell whereby air or other evaporativemedium can be introduced into the cell in a turbulent form and, at thesame time, permit the operator to view the spinning without removing thedoor or otherwise upsetting the spinning equilibrium.

These and other objects will more clearly appear from the descriptionwhich follows:

Briefly stated, my invention comprises a door or closure member adaptedto cover a complementary opening in the side-wall of the spinning cellclosely adjacent the spinneret; the door or closure member beingprovided with a sight opening covered with glass or other transparentmaterial not affected by the solvent vapor in the cell, and located topermit usual inspection of the zone about the face of the spinneret, acooperating light opening located to permit illumination of the zoneabout the face of the spinneret, and around the sight opening aplurality of air-directing slots through which air or other evaporativemedium is introduced into the cell in turbulent form.

The details of my invention are set out in the following description,reference being had to the accompanying drawing wherein Fig. 1 is afront elevation of a preferred form of the invention;

Fig. 2 is a cross-sectional view on the line AA of Fig. 1;

Fig. 3 is a cross-section on the line 3-3 of Fig. 1 and shows in detailthe construction of an air-inlet opening;

Fig. 4 is a front elevation of a modified form of construction;

Fig. 5 is a detail view of an alternate construction of light-opening;and

Fig. 6 is a cross-section on the line A-A of Fi 5.

In a preferred embodiment of my invention, illustrated in Figs. 1, 2 and3, the door or closure member is comprised of a panel I of appreciablethickness, which may be provided with any convenient means (not shown)of mounting the same in the side wall of the spinning cell, and over thecomplementary opening provided therefor. Centrally located with respectto the vertical axis of panel I is a sight-opening, preferably circular,provided with a glass retaining flange 2 adjacent the one face of thepanel and a recessed portion 3 adapted to receive a snap wire glassretaining ring 4, adjacent the opposite face of the panel. A pane 5 ofglass or other transparent material which is not afiected by the solventvapor is held in position by the flange 2 and snap-wire ring 4. Directlybelow the sight opening is a smaller funnel-shaped light-directingopening 6 which serves to direct a beam of light, from a flash-light orother convenient source, generally on or near the face of the spinneret.To either side of light-d1- recting opening 6, and below the sightopening are relatively long air-inlet slots 1 which extend radially withrespect to the center of the sight opening. Additional and relativelyshort air-inlet slots 8 are located on either side of the sightopeningand likewise extend radially with respect to the center of thesight-opening. Preferably slots 1 and 8 are centered 30 apart with onepair of the slots being centered on the horizontal axis of thesight-opening. All of the air-inlet openings slope at an angle,preferably of 30, to the plane of the face of panel I, as shown in Fig.3.

This arrangement gives very good turbulence and excellent spinning undernormal conditions when only one yarn is formed per spinneret and for thespinning of a single yarn from one spinneret this form of the inventionis preferred.

In the modification shown in Fig. 4, the short air-inlet slots 8' arecentered on, but have their longer axis at right angles to, the radiallines passing through the center of the sight-opening.

This modified arrangement of the slots, through which air is introducedinto the spinning cell, is especially desirable for double end spinning,i. e., the spinning of two threads from a single spinneret, inasmuch asthe small side slots divert the incoming air around the sides of thecell-head and thus prevent the filaments of the divided yarns fromstriking the cell walls.

In place of the funnel-shaped light-directing opening (Fig. 2) I mayemploy the construction illustrated in Figs. 5 and 6 wherein the openingis a slot of wedge-shaped cross-section, the apex of the wedge being atthe outer face, and the base of the Wedge being at the inner face ofpanel I.

It is to be understood, of course, that my invention is not limited tothe precise details of construction recited above, which are for pur--poses of illustration only, but is susceptible rather to a widevariation of arrangement and the substitution of obvious mechanicalequivalents. Thus, instead of a relatively thick panel portion, theclosure may be made of sheet metal or the like, and air-deflecting earsor flaps may be substituted for the sloped slots of the preferredembodiment described. Furthermore, the panel need not be separate fromthe cell but may be made integral therewith by modifying the cellside-wall at the appropriate point in accordance with the spirit of myinvention. Finally the glass or other transparent material may bemaintained in position by any one of a number of obvious mechanicalexpedients. The only essential requirement is that the generalorganization of sight-, lightand air-inlet openings disclosed herein beobserved.

By use of my invention, the operator 'can shine a light through thewindow and readily determine whether or not 'all the holes in thespinneret are free and passing their portion of the spinning solution,and at the same time there is made possible the introduction of theevaporative medium into the cell with the desired turbulence.

I claim:

In an evaporative spinning apparatus comprising a spinning cell having aspinneret within the upper portion thereof, arranged for double endspinning, the improvement which comprises a relatively thick closuremember adapted to cover a complementary opening in the side wall of thecell closely adjacent the spinneret, said closure member being providedwith a circular sight-opening covered with transparent material, alight-opening directly therebelow, and a plurality of air-inlet openingsdisposed in a circle about said sight-opening, said air-inlet openingscomprising two relatively long slots located below the sight-opening andextending radially with respect'to the center of the sight-opening andat an angle of 30 from the vertical axis of the sight-opening, and aplurality of shorter slots extending at right angles to radial linesfrom the center of the sight-opening and located above said long slotsand to each side of the sight-opening, each of said slots extending thruthe relatively thick closure member at an angle of 30 with respect tothe face of said closure member and toward the adjacent wall of thespinning cell whereby evaporative medium entering the cell thru saidslots is directed around the walls of the spinning cell.

JAMES J. CALHOUN.

